Lawmakers have updated the statute over the years, but disagreements linger in 2011 over how best to revise it again. In addition, the Department of Justice has actively avoided changes to the ECPA that might curtail its broad powers — maligned by privacy hawks and civil libertarians alike — to investigate crimes involving digital evidence.

At the same time, federal courts are weighing cases that threaten the DoJ’s use of the law. Only last week, reports surfaced that the DOJ secretly sought at least one individual’s email contacts as part of a federal investigation into WikiLeaks — an activity permitted under the ECPA, though one that led critics to argue for revisiting its provisions.

In general, the ECPA sets the ground rules for how law enforcement can access electronic communications. To critics, it is inconsistent: It sometimes affords less protection to data stored on servers than it does documents in a filing cabinet, and it makes it easier for the government to access data stored for longer periods of time.

“We’re just asking that the law reflect what probably most people assume it already says, which is that if the government wants to intrude that deeply on my privacy, they ought to get a warrant from a judge,” said Jim Dempsey, vice president for public policy with the Center for Democracy & Technology.

But to law enforcement, the ECPA is critical precisely because of those different standards. It allows investigators easy access to simple data, like an Internet provider’s subscriber information, yet raises the bar for more personal data, such as the real-time location of a suspect tracked via their smartphone.

To the DoJ, the law “properly strikes the balance of public safety and privacy the way it is,” said Jason Weinstein, deputy assistant attorney general at the agency’s Criminal Division, during an interview. But he added that Justice is “open to discussing surgical amendments to make the statute clearer.”

Still, the fight for revising the ECPA has attracted some unlikely Washington bedfellows — including the American Civil Liberties Union, Americans for Tax Reform, the Competitive Enterprise Institute, CDT, Google, Microsoft and more. They may not move totally in lock step on all issues related to ECPA reform, but in a few major areas, they are among many players operating under the banner of the Digital Due Process coalition.

Some celebrated the law’s 25th birthday this week by ramping up efforts to change it in Congress. A handful of groups Tuesday also highlighted on Capitol Hill new bipartisan Senate support for addressing one of the ECPA’s key issues — the treatment of location data — at an event showcasing the seemingly antiquated computers that typified the decade when the ECPA came into existence.

Some lawmakers agree that in this age of smartphones and cloud computing, it’s time for a change for the ECPA. Yet updating the statute has mostly proved elusive.

The most prominent champion of ECPA reform to date has been Sen. Patrick Leahy (D-Vt.), chairman of the chamber’s Judiciary Committee, whose comprehensive reform bill has broad industry support. Its signature element would generally require law enforcement to obtain a search warrant before accessing some digital records — an idea the DoJ opposes as too restrictive. But Leahy’s bill has no Republican backing, and no markup on it has been announced.

The senator told POLITICO in a statement this week that he remains committed to the issue.

“When Congress passed ECPA 25 years ago, we could not have contemplated the advances in technology that have spurred new privacy concerns for consumers,” Leahy said, adding that an update is “essential to ensuring that federal privacy laws keep pace with new technologies and the new threats to security.”